Field of the Invention
The present disclosure relates to sheet feeding apparatuses and image forming apparatuses, and in particular, to a configuration for holding a restricting member that restricts the trailing end of sheets.
Description of the Related Art
Widespread image forming apparatuses, such as copying machines, printers, and facsimiles, are equipped with a sheet feeding apparatus from which sheets are fed to an image forming unit to form images. Typical examples of such a sheet feeding apparatus feed sheets in a sheet cassette provided in an image forming apparatus main body to the image forming unit using a feed roller.
The sheet cassette is provided with a trailing-end restricting member that aligns the trailing ends of the contained sheets in a sheet feeding direction (hereinafter referred to as “trailing end”) and a side-edge restricting member that aligns the side edges of the sheets in a direction perpendicular to the sheet feeding direction (hereinafter referred to as “cross direction”). In such a sheet cassette, the leading end of the sheets are always aligned in position by restricting the side edge position of the sheets using the trailing-end restricting member and by restricting the trailing end position of the sheets using the side-edge restricting member. This enables stable sheet feeding regardless of the size of the sheets contained in the sheet cassette.
A known sheet cassette in the related art can give a sense of clicking to a user who is placing standard-size sheets, such as A3 or A4, in the sheet cassette when the user moves the trailing-end restricting member to a position at which the trailing ends of the sheets are aligned (Japanese Patent No. 4563309). The sheet cassette has engaged portions at every standard-size positions on a rail on which the trailing-end restricting member moves. By elastically engaging one of the engaged portions with an engaging portion of the trailing-end restricting member, the user is given the sense of clicking.
Image forming apparatuses are decreasing in size to enhance space utilization. The decrease in the size of image forming apparatuses can make the image forming apparatus main body smaller than sheets for use. To address this, a sheet cassette provided with a drawer member that can be drawn together with the trailing-end restricting member is disclosed in Japanese Patent Laid-Open No. 2008-184297. The drawer member is drawn for use according to the size of the sheets. With this configuration, the drawer member is drawn for use only when large-size sheets are to be held, in other words, the drawer member is drawn only when large-size sheets are to be used. This solves the problem of the installation space.
In the sheet cassette provided with an extension cassette, which is the drawer member, the trailing-end restricting member is held in the extension cassette so as to be slidable in the sheet feeding direction. The claws of the trailing-end restricting member engage with a rack gear at the bottom of the extension cassette to restrict the movement of the trailing-end restricting member.
Another example of the sheet cassette holds non-standard-size sheets, in addition to the standard-size sheets. An example of this sheet cassette is separately provided with a retaining unit for retaining the trailing-end restricting member at a position at which the trailing end position of standard-size sheets is to be restricted and a retaining unit for retaining the trailing-end restricting member at a position at which the trailing end position of non-standard-size sheets is to be restricted (Japanese Patent Laid-Open No. 2007-223686).
In general sheet cassettes provided with the extension cassette, the trailing-end restricting member is slidably mounted to the extension cassette. The retaining unit for retaining the trailing end position of non-standard-size sheets and the engaged portion for standard-size sheets for giving the sense of clicking at the trailing-end restricting member are also provided at the extension cassette.
Suppose a sheet cassette capable of holding letter-size sheets of landscape orientation in a state in which the extension cassette is pushed into the sheet cassette and capable of holding ledger-size sheets of portrait orientation in a state in which the extension cassette is drawn. With this sheet cassette, in holding relatively small standard-size sheets, such as letter-size sheets of landscape orientation, A4-size sheets of landscape orientation, B5-size sheets of landscape orientation, or A6-size sheets of landscape orientation, the extension cassette is in a pushed state. This extension cassette is provided with an engaged portion (an engaged portion for small-size sheets) for giving the user the sense of clicking at a position corresponding to the trailing ends of standard-size sheets in a state in which the extension cassette is pushed into the sheet cassette.
In holding relatively large standard-size sheets, such as ledger-size sheets of portrait orientation, legal-size sheets of portrait orientation, A3-size sheets of portrait orientation, or B4-size sheets of portrait orientation, or large non-standard-size sheets, the extension cassette is drawn from the sheet cassette. When the extension cassette is thus drawn, the engaged portion for small-size sheets can come to the vicinity of the trailing ends of large standard-size sheets or large non-standard-size sheets.
When the trailing-end restricting member is set at a position at which the trailing end position of large standard-size sheets or large non-standard-size sheets is to be restricted in this state, the trailing-end restricting member can engage with the engaged portion for small-size sheets, in which case the user has the sense of clicking. The sense of clicking causes the user to recognize that the trailing-end restricting member is held at a position at which the trailing end position of large standard-size sheets or non-standard-size sheets are to be restricted. However, the trailing-end restricting member is not held at the position at which the trailing end position of large standard-size sheets or non-standard-size sheets is to be restricted, in other words, the trailing-end restricting member is held at an improper position. This can cause trouble in sheet feeding.